DESCRIPTION: Prospective epidemiologic data indicate a strong relationship of chronic anxiety and/or anxiety disorders to risk of sudden cardiac death. Other studies have shown that cardiac autonomic mechanisms are altered among stably anxious individuals in the direction of reduced parasympathetic and elevated sympathetic control. The latter investigations, however, have been based on very small clinic samples and been incomplete in their assessment of cardiovascular regulation in anxiety. The goal of the proposed study is to evaluate the hypothesis that chronic anxiety and/or anxiety disorders result in hyperkinetic cardiovascular autonomic regulation, often associated with increased coronary risk. The project will use an ongoing well-characterized cohort, the VA Normative Aging Study (NAS), to recruit middle-aged and older community- dwelling man and women into the study. Using a variety of validated psychological and psychiatric screening instruments--including the Brief Symptom Inventory, the Composite International Diagnostic Interview, the Spielberger State-Trait Anxiety Inventory, and the Crown-Crisp Index-- the study population will be characterized in terms of symptoms of anxiety and diagnosis of anxiety disorders. Cardiovascular autonomic control will then be assessed among anxious and non-anxious individuals using non-invasive time-domain and power-spectral measures of heart rate and blood pressure variability. Cardiac output, total peripheral resistance, and end-tidal pCO2 will be simultaneously assessed. This investigation will be the first large-scale population-based research examining the cardiovascular physiology of anxiety, and should increase one's understanding of the reported association between anxiety and sudden cardiac death. This study may further help to identify groups in the general population who are at increased risk of sudden death.